Light sources are widely used in a wide range of ambient lighting applications for creating a particular lighting atmosphere at various locations such as rooms. Professional indoor lighting applications, aimed at offices, shops, hotels, etc., are particularly important areas of application.
For example in office environments, it is often desired to provide direct (functional) lighting for workspaces and indirect lighting for providing general lighting of the environment. Light fixtures with indirect and direct lighting have been introduced in order to provide lighting conditions that are considered to improve productivity and occupant satisfaction. Even though these parameters may be hard to quantify, the benefits of such lighting conditions are considered to be significant. Particularly in lighting applications aimed at offices, but also for example in other professional indoor lighting applications, there is generally a requirement on the collimation angles of the emitted light. Collimation of the light generally reduces glare. In order to meet requirements for reduction of glare, lighting systems may be provided with optics using refraction and total internal reflection (TIR) for collimation of the light and/or reflecting (metal) collimators. Such lighting systems may for example be based on light-emitting diodes (LEDs).
Light-emitting diodes intended for indication purposes have been used for a long time, whereas high-brightness LEDs, e.g. LEDs having a brightness that is high enough to enable general illumination of various locations such as rooms, have in a short period of time caused a significant growth in the LED and lighting applications market. High-brightness LEDs are generally associated with a small size, a relatively high efficacy (and associated low temperature), a relatively long lifetime, a wide color gamut and ease of control. Naturally, such LEDs are of importance to lighting designers in developing new lighting applications. Such LEDs may also be utilized in replacing conventional light generation devices, such as filamented light bulbs or halogen lamps. Such LEDs are also generally capable of emitting light of various colors.
Lighting systems have been developed for complying with glare norms. For example, lighting systems employing different techniques to shape light from a diffuse light source into a well-defined (collimated) light beam are known.
WO 2009/087587 A1 describes a lighting system comprising a light guide having a first and a second surface facing each other, at least one of the surfaces being able to provide light in a first direction. The lighting system further comprises means capable of providing light, the means being disposed on one of the surfaces, and means for shaping light from the means capable of providing light.